Such an electromagnetic dual clutch-brake combination is used for the optional drive connection of a drive input shaft to a first or to a second drive output shaft. Depending on the shift condition of the dual clutch-brake combination, a single electric motor coupled to the drive input shaft can drive the first drive output shaft or the second one.
A dual clutch-brake combination of the type described is disclosed in DE 100 58 199 A1.
Such a dual clutch-brake combination can be used in the drive train of an all-wheel vehicle with range shifting between a fast and a slow operating range and a variable longitudinal differential lock. In the vehicle's drive train a shiftable, two-stage range gear system is arranged after the main gearbox, such that the first stage corresponds to the slow drive range and the second stage to the fast range. The range gear system comprises a shift element in the form of a claw or disk clutch or a synchromesh, which can, be actuated by the first drive output shaft of the dual clutch-brake combination via an actuation mechanism. When the second drive output shaft of the dual clutch-brake combination is rotating, then depending on the rotation direction, a disk clutch is closed further or opened further, which depending on its degree of closure transfers a certain torque between the two drive axles of the vehicle. If the disk clutch is fully closed, the front and rear axle differentials are driven at the same speed.
The dual clutch-brake combination according to DE 100 58 199 A1 thus enables a single electric motor optionally to shift the two-stage range gear system or to actuate the variable longitudinal differential lock. The drive input shaft of this dual clutch-brake combination can be braked to rest by an electromagnetic brake. A static torque exerted on the drive input shaft by the electric motor can even be maintained when the electric motor is not under load in that the brake is applied before the electric motor is turned off. The electric motor is unloaded and the overall consumption of electrical energy is reduced. A frequently encountered driving situation on difficult ground is to start with a closed longitudinal differential lock in the slow driving range. When the vehicle has reached a certain speed, a shift to the fast driving range is necessary. If a dual clutch-brake combination such as that described in DE 100 58 199 A1 is used, the driving range can only be shifted if the variable longitudinal differential lock is opened briefly.
Accordingly, the purpose of the invention is to indicate a dual clutch-brake combination with which a shift of the range gear system can take place, while the torque transferred by the variable longitudinal differential lock between the drive axles remains unchanged even during the range shift.
This objective is achieved by an electromagnetically actuated dual clutch-brake combination.